A shot of prevention

On Magic Johnson, Princess Di, and a drug trial that went so well it had to be cancelled prematurely

When Magic Johnson revealed his HIV diagnosis to the world in 1991, even he thought it was a death sentence. For many people, it already had been, and there was no certainty at all about the future treatment of the virus. It had been headline-grabbing news just two years prior for Princess Diana to have hugged a young AIDS patient.

■ Pharmaceuticals have done amazing things in the years since -- Magic Johnson is still alive and tweeting to this day. Television commercials even advertise to a market for people living with HIV, which suggests that it's a demographic with at least some degree of critical mass.

■ But even with all that progress in mind, it is stunning to encounter the news that a drug trial was prematurely cut short because the drug had proven so overwhelmingly effective that it became unethical to keep anyone in the placebo group. A randomized trial of more than 5,000 women and girls in South Africa and Uganda came back with zero cases of HIV infection among more than 2,100 women receiving the drug.

■ The doses only need to be taken semiannually, so it's basically in vaccine territory. It's not exactly a vaccine in the normal sense, but since it's a shot that prevents the transmission of the virus, it has effectively the same result. The old wisdom about an ounce of prevention being worth a pound of cure is as true today as ever, so this news is profoundly good.